The invention relates to laryngoscopes of the type comprising a non-metallic blade for single or little-repeated use and a handle for intensive use, the blade and the handle being provided with respective means that co-operate to enable the blade to be assembled in detachable manner on the handle in at least one predefined position.
The means for assembling the blade on the handle comprise engagement means which enable the blade to be engaged on the handle, and spring effect locking means which act to hold the blade in the selected position but which can be made inactive by appropriate manipulation of the blade in order to be able to separate the blade from the handle after use.
Publication EP 0 169 497 describes an embodiment in which:                the engagement means comprise both a cavity situated in one end of the handle, which cavity is open to the outside-and contains a bar placed across the cavity, and a hook formed on a tab at one end of the blade so as to pivotally engage the bar when the tab is inserted into the cavity of the sleeve; and        the locking means are constituted by a wall provided on the handle beside the cavity and receiving the tab of the blade so as to come into wedging contact with a facing wall of the tab under thrust from a spring blade fixed on the handle.        
Since the handle is for repeated used, there exists a risk of fatigue in the spring blade, causing it to become less effective in locking the blade.
Publication GB 2 191 949 describes laryngoscopes having an adaptor between the blade and the handle. In one embodiment (FIGS. 4 and 5), where the means for engaging the handle on the adaptor comprise a bar and where the means for engaging the blade on the adaptor comprise a hook, the means for locking the handle on the adaptor and the means for locking the blade on the adaptor comprise respective spring-loaded balls. In another embodiment, where the means for engaging the blade on the adaptor comprise a screw passing through a tab of the blade and the adaptor, the means for locking the blade are constituted by a spring blade fixed to the tab of the blade and coming into abutment in a lateral cavity of the adaptor. Similar engagement means and locking means are provided on the handle.